1. Field of the Invention
The present invention relates to an image display field, more particularly, to an OLED packaging structure and the packaging method thereof.
2. Description of the Prior Art
Organic Light-Emitting Diode display device is a new generation of display device. By manufacturing an organic film on a substrate in a way that an organic film locates between a cathode metal and an anode metal, the organic film illuminates when voltage is applied to the two electrodes. As the organic film is highly sensitive to moisture and oxygen, its illumination and lifetime will be greatly affected by its aging and degeneration caused by moisture and oxygen. Therefore packaging process to OLED apparatus is necessary.
Please refer to FIG. 1, the conventional packing method is that: a. painting glass frit seal on a position which corresponds to an OLED on a packaging board 1′ to form a rectangle seal frame 3′ whose size matches the OLED, and solidifying the glass frit seal in a curing oven; b. painting ultraviolet light curing adhesive 4′ on the fringes around the packaging board 1′; c. adhering a packaging board 1′ and an OLED substrate 2′; d. UV adhesive 4′ is solidified under UV light (the effect of UV adhesive is to block moisture and to fix the packaging board 1′ and the OLED substrate 2′); e. melting the glass frit seal on every rectangle seal frame 3′ by using laser and adhering the packaging board 1′ and the OLED substrate 2′ by the congealed glass frit seal. A sealed cavity is formed through the packaging board 1′, the OLED substrate 2′ and the seal frame 3.
As FIG. 2 indicates, however, after the glass frit seal is painted, accumulation of adhesive appears on an initial painting point 30′. When the glass frit seal solidifies, a height of accumulation of adhesive at the initial painting point 30′ is higher than that of other region, thereby forming a gap 12′ between the glass frit seal nearby initial painting point 30′ and the OLED substrate 2′. After the glass frit seal is hardened, even if using pressing mechanism to press the packaging board 1′ and the OLED substrate 2′, the gap would not disappear (please refer to FIG. 3). Therefore the region around initial painting point 30′ cannot be successfully welded with OLED substrate 2′ in the process of laser welding due to gap 12′, which leaks moisture into the sealed cavity and affects the lifetime of OLED.